1. Technical Field
The present invention relates to a semiconductor integrated circuit, and more particularly, to a semiconductor apparatus.
2. Related Art
In general, a semiconductor apparatus inputs and outputs data through word lines and bit lines connected to memory cells.
FIG. 1A is a block diagram of a conventional semiconductor apparatus.
Referring to FIG. 1A, the configuration of the conventional semiconductor apparatus will be described as follows. First, a bit line BL is precharged to a precharge voltage Vpcg. At this time, in order to remove a voltage difference between the bit line BL connected to a selected memory cell T4 and a bit line unconnected to the memory cell T4 (hereafter, referred to as “bit bar line BLB”), the precharge voltage Vpcg is inputted to first to third transistors T1 to T3 (T1, T2, and T3) to equalize the two bit lines.
FIG. 1B is an operation timing diagram of the conventional semiconductor apparatus.
Referring to FIG. 1B, the operation of the conventional semiconductor apparatus will be described as follows. When a sense amplifier is not used, the precharge signal Vpcg is maintained at a high level such that the memory cell maintains the voltage levels of the bit line BL and the bit bar line BLB at a bit line precharge voltage Vblp. Before a signal inputted to a word line WL becomes a high level, the precharge signal Vpcg is changed to a low level to perform a charge sharing operation. The charge sharing operation causes a voltage difference of the sense amplifier (i.e. SA). At this time, however, the voltage of the bit bar line BLB increases or decreases due to parasitic capacitance C1 between the bit line BL and the bit bar line BLB (i.e., delta B). Therefore, the voltage change of the bit line BLB caused by the parasitic capacitance C1 may reduce a sensing ability of the sense amplifier. Furthermore, due to mismatch between transistors forming the bit line sense amplifier, an error may occur during data output. Accordingly, an offset measuring method for controlling the mismatch of the bit line sense amplifier is needed.